/Engine/Source/Runtime/Engine/Classes/Kismet/KismetRenderingLibrary.h
Incredibly inefficient and slow operation! Read a value as sRGB color from a render target using integer pixel coordinates. LDR render targets are assumed to be in sRGB space. HDR ones are assumed to be in linear space. Result is 8-bit per channel [0,255] BGRA in sRGB space.
static [FColor](API\Runtime\Core\Math\FColor) ReadRenderTargetPixel ( [UObject](API\Runtime\CoreUObject\UObject\UObject) * WorldContextObject, [UTextureRenderTarget2D](API\Runtime\Engine\Engine\UTextureRenderTarget2D) * TextureRenderTarget, int32 X, int32 Y )